Liquid fuel burning heater



March 30, 1954 3 BUDLANE 2,673,558

LIQUID BURNING HEATER Filed 001). l, 1948 9 Shets-Sheet 1 m INVENTOR. @5 2. 526172; JjZZCZZQ/Ze March 30, 1954 s. J. BUDLANE LIQUID FUEL BURNING HEATER 9 Sheets-Sheet 3 Filed Oct. 1, 1948 JNVENTOR. cfjzzd/azze BY 7 5,5244 0 M March 30, 1954 s. ,1. BUDLANE LIQUID FUEL BURNING HEATER 9 Sheets-Sheet 4 Filed Oct. 1, 1948 IN V EN T 0R. cffizdcid'azze March 30, 1954 Filed Oct. 1, 1948 S. J. BUDLANE LIQUID FUEL BURNING HEATER a Sheets-Sheet 5 March 30, 1954 Filed Oct. 1, 1948 S. J. BUDLANE 1 LIQUID FUEL BURNING HEATER I 193' i 184 PM 254' I k 224 231 232,238 I J 60 9 sheets-sheet 6 IN V EN TOR. jz czzz Of March 30, 1954 s. J. BUDLANE LIQUID FUEL BURNING HEATER 9 Sheets-Sheet 7 Filed Oct. 1, 1948 NEW QMN

IN V EN T OR. cfjza'adczme s. J. BUDLANE LIQUID FUEL BURNING HEATER March 30, 1954 9 Sheets- Sheet 8 Filed Oct. 1, 1948 INVENTOR- March 30, 1954 s. J.--"'BUDLANE LIQUID fun. BuRivINr; HEATER Filed Oct. 1, 1948 9 Shqats-Sheet 9 Patented Mar. 30, 1954 2,673,558 LIQUID FUEL BURNING HEATER Stanley J. Budlane, Chicago, Ill., assignor to Motorola, 1110., Chicago,

Illinois Application October 1, 1948, Serial No.

11 Claims. 126-116) heaters of this type utilizing liquid fuel.

There are many instances in which one may desire to utilize a liquid fuel-consuming air heater in a space of moderate size, such as an individual room or an area of a house or factory or the interior of a vehicle. Usually in these cases it is desired that the heater shall be inconspicushall have a compact, inexpensive construction. which a body of liquid fuel fed through a wickto a combustion chamber, are not generally satisfactory because th burner structure is apt to be very largein proportion to the heat obtainable therefrom, and usually a chimney is required on such a heater. Another type of heater utilizes a burner which atomizes the liquid fuel or otherwise breaks up the fuel particles mechanically to produce a spray which may be burned elficiently in a relatively small combustion chamber. A heater such as this, however, requires a large amount of power for its operation, so that the saving in space achieved by using a smaller combustion chamber is oiiset by the added space needed to accommodate the power equipment, as well as the added cost and operating expense involved. Such arrangements are practical only in large installations and are not generally considered suitable in an individual room heater, for examp Still another type of heater has been proposed in which the fuel is preheated to vaporize it and facilitate dispersal of the fuel particles in an air stream, thereby forming a combustible mixture which then'is'ignited in the combustion chamber. This method is advantageous in that the power requirement is low, efficiency is high, the equipment is not complex or expensive, and it occupies very little space.

The principle of household heaters. The difiiculty in such cases has been due partly to the conditions under which household heaters and the like generally are operated. The demands made upon the heaterfor heat :output; are :apt to: be .quite large (say,- of the order of 40,000 B. t. u. per minute), necessitate ing a liiglr-rateof1fuel.,ivaporization-. Butthis Ill.) incorporation of high rate of fuel vaporization has not been considered feasible heretofore (within any competisituation is further complicated by the fact that, for domestic purposes, it is preferable to use one of the heavier liquid fuels such as kerosene which is relatively cheap and non-explosive, but which also has low volatility. Many problems are entherefore, in attempting to provide a satisfactory household heater or the like which complies with all of the requirements mentioned above, and to date the industry has had to content itself with various compromises among these factors in order tuproduce marketable heaters.

For any particular heater using a specified liquid fuel, there is a certain optimum vaporization temperature to which the fuel should be heated in order to produce the most eificient combustion. In prior heaters, utilizing liquid fuel there has been an inherent tendency for the temperature of the fuel to vary depending upon the number of burners in operation and/or the vaporized to vary. This would cause the performance of the heater to, fluctuate in a very undesirable manner. Stabilization ofthe temperature at which vaporization occurs is a highly desirable feature not only in household heaters, but in substantially all heaters which consume liquid fuel and which depend for their successful operation upon the proper mixing of. fuel vapor with air prior to combustion thereof. 2 r

In view ofallthe foregoingconsiderations, it is a primary object of the present invention to provide an improved liquid fuel-consuming heaterfor small and medium-size domestic in stallations which successfullyembodies all of the features, such as small size, large heat output,

burners by being vaporized in a compact but highly heat-conductive environment containing a large quantity-of heat which is constantly-avail able-for transfer tothe fuel.

A further object is to utilize a small pilot flame for storing heat in the aforesaid heat-conductive environment, and particularly for maintaining the temperature thereof substantially constant at an optimum value which produces rapid vaporization of the fuel without premature burning or carbonization thereof.

A still further object is to provide an improved fuel conditioning means which tends to maintain itself at a constant temperature irrespective of the rate at which fuel is consumed in the heater, and an ancillary object is to accomplish this result without resorting to electrical means for maintaining the vaporizer heated.

A still further object is to provide a novel vaporizer block adapted to be maintained at a constant temperature by the pilot burner of a main bumers in operation or the rate of fuel consumption.

A still further insure thorough vaporization, mixing of the fuel with air, and combustion of the fuel by a continuous heating and agitating action of the fuel articles until they are completely consumed.

A still further object is to provide a small, economical household heater of the liquid fuelconsuming type which will operate more efficiently than heaters which are competitive in price, and which is absolutely safe and dependable in service.

A still further object is to replace the cast parts heretofore utilized in the combustion chambers and heat exchangers of fuel-burning heaters with light-weight, inexpensive sheet metal or tubular parts.

Additional objects are to provide a novel electric igniter, a novel operating system for a liquid fuel-consuming heater and a novel form of fuel feeding assembly, all of which contribute substantially to the over-all improvement of such heaters.

As one of the features of this invention, an integral metallic vaporizer block is formed with main burner and pilot burner ports therein and with fuel conditioning passages leading through the interior of the block to the respective ports. An electric igniter element, which is part of a fuel-burning igniter structure, is employed temporarily to establish a flame that passes throu h a seperate igniter port or flame passage in the block and is utilized to preheat the vaporizer block so as to establish vaporization of the pilot fuel and to ignite the combustible mixture issuing from the pilot burner port. The pilot flame burns continuously and is so disposed that a large share of the heat furnished by the pilot flame is contained temporarily in the vaporizer block, thereby maintaining this block substantially at a constant .temperature for optimum vaporization of the fuel .in the various conditioning passages. The fuel supply for the main burners is modulated according to heat requirements in the space that is being heated. Combustible mixture issuing from the main burner ports is ignited by the pilot flame. The aforesaid igniter flame is maintained only long enough to light the pilot flame and to provide an initial heating of the vaporizer block, then is extinguished.

Another feature is the provision of a cylindrical combustion chamber for each main burner so arranged with respect to the vaporizer block that a main burner flame is caused to impinge tangentially against the interior wall of the chamber and is directed in a whirling path around the tubular axis, causing the heavier fuel particles to be completely broken up, promoting efficient and complete combustion of the fuel, and providing for stable burner operation by nature of the design so that the burner is (to a certain extent, at least) self -piloting in action.

Still another feature is the arrangement of heat exchanger tubes in relation to the individual combustion chambers whereby hot combustion products are directed substantially without flame into the heat exchanger tubes. Each combustion chamber itself is in the form of a tube having relatively small dimensions and mounted on'the vaporizer block.

Still another feature is the compact arrangement of air intake and exhaust ducts, air plenum chambers for inducing fuel feed and proportioning the admission of air to the various conditioning passages, a combustion air blower assembly which is thin and flat so that it occupies very little space, heat exchangers on either side of the vaporizer block communicating with the burner tubes, and air circulating means disposed in roximity to the heat exchangers.

Still another feature is the mounting of the heat exchangers, burner structure, fuel vaporizing block and fuel feeding package on a tubular supporting member which serves also as an intake air duct for the heater.

Still other features reside in the construction of various components such as the igniter and fuel feeding package, which will be brought out more in detail hereinafter. Numerous other features and advantages will be apparent from a study of the following detailed description taken in connection with the accompanying drawings, wherein:

Fig. 1 is a perspective view showing a heater constructed in accordance with and embodying the principles of this invention, the heater being shown mounted on a wall in a room or other enclosure;

Fig. 2 is a front perspective view of the heater with its housing removed, showing parts of the structure broken away for clarity of illustration;

Fig. 3 is a vertical sectional View of the heater shown in Figs. 1 and 2;

Fig. 4 is a vertical section on the line 4-4 of Fig. 3;

Fig. 5 is a horizontal section of the vaporizer block taken on the line 5-5 of Fig. '7;

Fig. 6 is a rear perspective view of the burner assembly of the heater (removed from its case) together with associated parts;

Fig. '7 is a rear elevational view of the vaporizer block;

Fig. 8 is an elevational view of a diffuser or balancing plate adapted to be mounted on the rear of the vaporizer block;

Fig. 9 is a fragmentary front perspective view of the burner assembly, showing the main burner nozzles and the pilot flame baflle mounted on the front of the vaporizer block;

Fig. 10 is a fragmentary front perspective view of the vaporizer block;

Fig. 11 is a plan view of the fuel feeding package, taken on the line H-H of Fig. 3;

Fig. 12 is a vertical section on the line l2-I2 of Fig. 11;

Fig. 13 is a vertical sectional view taken on the line l3-l3 of Fig. 3, showing the fuel feedmgpackage and the electric igniter unit in elevation, certain portions of the structure being grzkialn away to illustrate otherwise concealed e a s;

Fig. 14 is a longitudinal section through the electric igniter Fig. 13;

Fig. 15, in the main, is a longitudinal section through the fuel pump and the pressure regulator of the fuel feeding package;

Fig. 16 is a sectional view of a fuel and air unit taken on the' line 14-14 of operation of the heater;

Fig. 18 is a vertical sectional view on the line I8-l8 ofFig.17; Fig. 19 is a detail sectional view on the line |9 |9 of Fig. 18, showing another switch; and

Fig. 20 is a circuit diagram of the heater operating system. In practicing the invention, the heater is con structed so that it may be mounted on an out- The heater has a burner assembly which includes a vaporizer block in which are formed fuel conditioning passages that extend through the interior of the block respectively to the main burners and to the pilot burner. The pilot flame serves the dual purpose of lighting the main vaporizer block has sufiicient mass so that a substantial quantity of heat from help support combustion at the burners.

The main burners are cut in and out selectively heat requirements. accomplished by modulating the fuel supply only, leaving the supply of combustion air unaffected. Cutting a main burner in or out does not disturb the desired sages and combustion chambers of the various burners are isolated one from another. An electrically operated, fuel-burning igniter is provided to effect an initial heating of thevaporizer block and to light the pilot flame. The igniter has its own electrically heated fuel preheating section for conditioning a combustible-fuel and air mixture which is ignited by a hot-wire element.

The burner structure of the heater includes tubular members which respectively serve as combustion chambers for the burner tubes directeach main burner flame in a whirling path which insures complete vaporization of the fuel and efiicient and stable combustion thereof. The hot products of combustion then are discharged into heat exchanger tubes equipped with fins for. transferringtm heatto the circulating air.

main burners. These The heat exchangen is; in two sections whichresp'ectively extend from either sideof the case in which the burner assembly is mounted. The combustion products are directed in U-shaped paths, being discharged into the exhaust duct near the point of entry of the fresh combustion air into the heater. There are numerous other features of my improved heater construction which will become more apparent as the description proceeds.

Referring now to Fig. 1, the heater 22 is mounted on the outside wall 24 of a room or enclosure and is supplied with liquid fuel from a concealed storage tank through a pipe or tubing 23. The heater 22 is provided with a suitable housing 28 having openings 32 at the bottom for drawing in air which is to be heated. The heated air isdischarged at the top of the heater through suitable discharge openings 30. A control knob 34 on the heater is set in accordance with the air temperature which is desired, and the heater automatically maintains this temperature within close limits. Referring now to Fig. 2, which presents a general view of the heater with its housing removed, the heater as a whole is mounted on a vertical plate 36 which is attached in any suitable fashion to the wall 24.

mounted in the case 40. In back of each heat exchanger section 38 there is disposed a removable can 42 adapted to hold water for humidifying purposes. Beneath the heat exchanger sections 38 are located a pair of air circulating fans 44, Figs. 2 and 3, mounted on a common shaft 45 which is driven by an electric motor 48. The motor 48 is mounted on a bracket 50 secured to the vertical supporting plate 36. The fans 64 are disposed in orifices 5| formed in the downwardly extending portions of angle plates 52 secured to the vertical plate 36. A shroud 54 extends laterally between the vertical portions of the plates 52 to deflect the incoming air toward the fan blades 44. Cool air is drawn in from the botheater through the openings 32 and is forced upwardly past the heat exchanger sections 38 by the fans 44, then is discharged through the openings 36, Fig. 1, after being heated.

The burner assembly of the heater is enclosed in the case 40, which is permanently secured to the heat exchanger sections 38. The burner case 40 is detachably secured to a back plate 56 by bolts 53 or other suitable fastening devices, Figs. 2 and 3. An air intake duct Eli and an exhaust duct 62, Figs. 3, 4 and 6, are welded or otherwise bonded to the back plate '56 and also to a mounting plate 64 which is disposed adjacent the inner surface of the mounting plate 36. Bolts 66 serve to fasten the mounting plate 64 to the plate 36. The plate 64, through the medium of the ducts 60 and 62, supports the entire burner assembly disposed in the case 40, as well as the heat exchanger sections 38, in horizontally spaced relation to the vertical rear plate 36.

The heart of the burner assembly is the vaporizer block 70, Figs. 3, 6, '7 and-10. This vaporizer block is an integral body of metal, preferably cast aluminum, which is bolted to a gasketed plate 72 (Fig. 3) that is connected by tubes M and 76 to the back plate 56 of the burner assembly. The functions of the tubes 74 and 16 will be explained more fully hereinafter. For the present it will enoted merely thattthey serve t support th vaporizer blockflll'ini the position'shown'.

The rear portion of the' block 10 is recessed,

indicated at I8, Figs. 3, and '7, to afford a plenum chamber. Communicating with this plenum chamber are three fuel conditioning passages 88, 82 and 84 which extend horizontally through the interior of the vaporizer block I8 from rear to front thereof. Combustion air is supplied to the plenum chamber 18 through the air intake duct 88 and the air tube 14. which communicates with the duct 68. From the chamber I8 the air is distributed to the passages 88, 82 and 84 through sets of openings 86, 88 and 98 respectively (Fig. 8) formed in a diffuser or balancing plate 92 disposed in the chamber I8. The balancing plate 92 insures that air will be admitted to the passages 88, 82 and 84 in the correct proportions.

Fuel is deposited in the passages 88, 82 and 84 to be vaporized therein, as will be explained in greater detail subsequently, and the fuel vapor is mixed with the air in each of these passages to form a combustible mixture. The passages 88 and 84 supply the combustible mixtures to the main burners of the heater, while the passage 82 supplies combustible mixture to the pilot burner. All of these passages are rectangular in cross section with flat, horizontal bottom surfaces on which the fuel is deposited to spread in a thin film thereover and become vaporized. The vaporizing surfaces are shown in the drawing as being smooth, but they may be corrugated or grooved if desired. It will be noted that the fuel conditioning passages have walls of substantial thickness or depth within the vaporizer block I8.

The burners themselves are shown best in Figs. 3 and 9. A rectangular front plate 94, having flanged edges which engage the interior of the burner case 48 on all sides thereof, is secured by screws 98 to the front of the vaporizer block 18. Projecting diagonally forward in diverging fashion from the plate 94 are the upper and lower main burner nozzles 98 and The plate 94 is suitably age. The nozzles 38 and I88 communicate through openings in the plate 94 with the forward ends of the fuel conditioning passages 88 and 84.

The pilot burner comprises a central rectangular port or recess I82 and a bafiie I88 at the front of the vaporizer block I8. A thin partition intervenes between the recess I82 and the fuel conditioning passage 82, and perforations I84, Figs. 3, '7 and extend through this partition. This perforated partition prevents the pilot flame from backing up into the fuel conditioning passage 82. The bafile I86 is mounted on the front plate 84 intermediate the nozzles 88 and I88 by a pair of the screws 95 (Fig. 9). This bafiie I88 forms a combustion chamber for the pilot flame, and the flame circulates within this chamber with a sort of self-piloting action so that the flame is not blown away from the fuel port I82. Openings I88 and H8 in the bafile I88 pilot flame to spread toward the main burner nozzles 98 and I88.

Each main burner has an individual combustion chamber consisting of a short length of tubing H2 or II4, open at both ends, which is disposed so that the main burner flame issuing from the nozzle 98 or I88 is caused to travel in a whirling path inside of this tube. The tubes H2 and I I4 are supported in the front part of the burner case 48 by a spider H8 (Fig. 3), permanently bonded to these tubes, which is attached by screws to the baflle I86. The axes of the tubular combustion chambers H2 and H4 are disposed transversely of the fuel and 84-, and ithe nozzles and .l88i'extend I88, respectively. gasketed to prevent leakallow portions of the conditioning passages 88 through openings I18 and I28 in these tubes to terminate in tangential relationship with the interior walls of the tubes. The openings H8 and I28 are sufficiently large so that portions of the pilot flame can be drawn into the interior of each tube by aspirating action. The tubes I I2 and H4 are made of suitable flame-resistant material (such as the nickel-chrome alloy sold under the trade-name Iconel) and may, if desired, be coated with a ceramic cement. The tubular combustion chambers for the main burners (I I2 and H4) have what may be termed a self-piloting effect, that is, they cause theflames to stay close to the main burner nozzles 98 and. I88 instead of separating therefrom, as might otherwise occur. Hence, they reduce the possibility of accidental extinguishment.

Referring now to Figs. 3, 5, 7 and 10, the vaporizer block I8 is provided with three additional interior passages I28, I22 and I24 which respectively extend from the pilot flame opening I82 rearwardly through the block for a limited distance, terminating in spaced relation to the plenum chamber 18. Small transverse apertures I26, I28 and I38 in the side of the block 18 respectively communicate with the inner ends of the passages I28, I22 and I24. As explained previously, only a portion of the pilot flame escapes through the holes in the baffle I86 for igniting the main burner fuel. The remaining portions of the pilot flame (or the combustion products therefrom) are forced rearwardly through the passages I28, I22 and I24 and escape through the openings I28, I28 and I38 to the exhaust space surrounding the block 18. The path of the pilot flame jets through the block 18 is indicated by the arrows in Fig. 5. The pilot flame thus serves to heat the vaporizer block 18, and it maintains the block 18 substantially at a constant temperature for optimum vaporization of the liquid fuel in the conditioning passages 88, 82 and 84. On the other hand, the main burners do not appreciably affect the temperature of the block I8, because of the low heat conductivity of the thin metallic connections between these parts (except to compensate for the cooling effect of the fuel).

When the heater is initially placed in operation from a cold condition, an ignition means is employed for warming the vaporizer block 18 and lighting the pilot flame. Referring to Figs. 3, 6, 13 and 14, the igniter I32 has a hollow cylindrical body or housing I34 that is connected near its lower end by the aforesaid tube 16 to a horizontal passage I38, Figs. 3, 7 and 10, that extends entirely through the vaporizer block 18 from the plenum chamber I8 to the pilot flame port or opening I82. The tube 18 and another tube 234 (mentioned hereinafter) serve to support the igniter housing I34 in the position shown in the drawing.

Centrally disposed within the igniter housing I34 is a metal tube I48, within which is mounted a coiled hot-wire element I42. The element I42 is formed out of bare resistance wire such as Nichrome. One end of the wire I42 is welded to the open end of the tube I48, as indicated at I44. The other end of the wire I42 is secured to a stud I48 that extends through the upper end of an insulating liner I48 in the upper end of the tube I48. A brass ring I58 surrounds and is secured to the upper end of the tube I48 and to the liner I48, and this ring I58 is pressfitted or otherwise secured to the ..inside or an internally threaded mounting nut I52.' The outer threaded end of the terminal stud I46 receives a nut I54 which is insulated from the mounting nut I52 by an insulating washer I56. An externally threaded bushing I58 is secured to the upper end of the hollow igniter body I34.

The tube I40, wire I42, liner I48, terminal stud I46, nut I54, ring I50 and nut I52 constitute a unit which is insertable in and removable from the igniter housing I34. The nut I52 is threaded onto the bushing I58 for securing this unit in the position shown Liquid fuel and air are delivered to the annular space surrounding the tube I40 in a manner which will be explained hereinafter. The upper portion of the wire I42 has a number of rather widely spaced turns which serve to heat the upper portion of the tube I40 to a temperature sufficient for vaporizing the fuel so that it will mix readily with the incoming air. The mixture of fuel vapor and air is funneled through a tubular sleeve I60 having flared ends which are secured inisde the igniter housing I34 closely adjacent to, but spaced from, the lower portion of the tube I40. For the purpose of elongating the path that must be travelled by the fuel and air and thus insure complete vaporization, a thick wire I62 is spirally wound on the exterior surface of the tube I40, to which it is secured. The fuel and air mixture therefore travels in the space between the tube I40 and the sleeve I60, so that the fuel is thoroughly heated,vaporized and mixed with the air to form a combustible mixture.

' The combustible mixture emerges through an opening I64 (Fig. 14) in a washer or flange I66, striking the bottom of the and part of the mixture whirls about into contact with the lower end of the wire igniter element I 42. The turns at the lower end of the element I42 are closely spaced together, and are heated to incandescence by the electric current passing through them, so that the combustible mixture is readily ignited upon coming into contact with the igniter'element I42. The igniter flame then is forced out through the tube 16 and through the passage I38 of the vaporizer block 10, emerging into the space I02 at the front of the block 10 and striking the baille I06.

The igniter flame serves to light the combustible mixture issuing through the perforations I04 from the pilot fuel conditioning passage 82 in the block 10, thereby establishing the pilot flame. The igniter flame also supplies a certain initial heating of the block 10 as it travels through the passage I38 in the block 10, and as portions of the igniter flame (or combustion products therefrom) pass backwardly through the passages I 20, I22 and I24 in the block 10. The flame passages I26, I22, I24 and I38 are in sufficiently close proximity to the fuel conditioning passages 80, 82 and 84 so that very rapid heating of the walls of the latter passages takes place, even under extremely cold ambient conditions.

The delivery of the liquid fuel to the heater is controlled by a fuel feeding assembly I10, Figs. 3, 6, ll, 12, 13 and 15. which is mounted on a manifold structure I1I secured to the air intake duct 66 rearwardly of the back plate 56 of the burner member I12 f the manifold structure I1I is secured to a base or body I 14 which'is seated on and welded to the duct 60.

Mounted on top of the frame I12 are a lower plate I16 and an upper plate or body I 18, between which a gasket is inserted. The plates I16 and 518 are secured together by screws I that are threaded into the member I12. The upper plate or body I18 has vertically extending ears I82 (Figs. 3 and 11) which support an electric solenoid pump I84, and a post or block I86 (Figs. 11 and 15) on which a fuel pressure regulator I88 is mounted. Also mounted on the upper plate I18 of the fuel feeding assembly is a row of four solenoids I00, I9I, I92 and I93. The solenoids control the flow of fuel to the igniter, pilot burner and main burners of the heater.

Structural details of the means for handling the liquid fuel, including the fuel feeding assemfitting I96, Fig. Assuming that the pump I84 diaphragm I98 is caused to oscillate by a reciprocatory plunger 200 of the solenoid 202. As the is retracted, liquid fuel is drawn past the check valve 204 into the fuel chamber 206 in the pump I84.

11 and 13, in the lower plate I16. The passage 2I2 interconnects a series of wells 2I4 in the lower plate I16 which are respectively located beneath the solenoids I90, Fuel therefor is supplied through the passages 2 I 0 and 212 to the various wells 2 I4.

In each of the fuel wells 2I4 is disposed a hollow boss 2I6, Fig. 12, which depends from the upper plate I18. Within each boss 2I6 is disposed a needle valve 2I8 which is controlled by a solenoid as I9 I, for example.

The interior of the boss 2 I 6 communicates with the well 2I4 so that fuel is admitted to the space valves 2I8 is associated with the upper end of a nipple 220 which the well 2I4 below the lower plate I16. A small burner and pilot burner solenoids I III, I02 and Incoming air flowing through the duct a passage 228 in the rear of the mani- I14.- A partition 226 (Fig. 16) in this the body I14 directs the air upwardly from the passage 228 into a small plenum cham- 230, Fig.- 13, within the frame I12 of the manifold structure I1iI. The air then flows into depends from the bottom of fuel conditioning passage fuel conditioning'passag'e 82 (Fig. 3); the'upper ma'in'burner fuel'conditioning passage 80-and the lower main burner fuel'conditionin'g passage 84. The action of these aspirator's is such that'iiquid fuel is drawn into the'fuel'line's and is bubbled through these line'sto the" fuel conditioning passages leading tothe burners. A

'Insimi1ar fashionffuel'fi'o'wing through the valve 2l8' controlled" by the igniter fuelsolenoid l90is drawn by aspiratin'g action'into'a tube 234, 20

FigSYBI 1'3'a1'1d l,tliat'leadsffroin the ple num chainber 230 to the interior of the ignit'er housing I34, In "this manner, thefflll is supplied to the igniter I32 under control of the solenoid I90.

A cut out'236' in the "rear mounting plate 36; Figs, "4' and13f'pr'ovides clearance for thefuel um I84 and the pressure regulator I88. Referrihghoiv to Fig. 15; thesole'noid' 202 of the pum 184 has *a" housing "238 fro'rn'the base of which'prb'jectsjan externally threaded collar-portion 24minwniehithe' mn er 200 is guided. The plunger 2 00 normally is n'iaintained'in spaced relation to the stationary fpole piece 242 by a spring 244 disposedwithin the diaphragmhous mg 245 "The diaphragm liousingflfidsiinountd on' an" internally threaded'retainin'g? ember or nut 248"Which' is Screwed onto "the eena'r 240. Iij'a'djustmentof the air gap between the plunger 200' and"pole piece 242 is; desired," a convenient way of doing this is to inselt'shinls between the base of the solenoid housingif238fand thscooperating end of the nut"248'(or the diaphragm housing' 246)" before the collar'240 andriut 248' are tightened. l 4 x A bolt-250 extends from th? plunger 200 through the pole piece ug 'ehd "ha a sh me:

tion connection 252 with contacts254mounted on the outside of the solen'oi housing 238. The

solenoid 202 cann'otbe energizedunless the con When the seIenoid 202 tacts 254 are "engaged.

is "energized, the plunger 200is retracted from" the position shown inFigJl'E} toward ,the pole' piece 242, thereby actuating the diaphragm l98 to draw a charge of fuel into/the chamber206g Due to the slip friction connection, the contacts 254 are not disengaged until 'the'plunge'rf200' nears the end of its rearward stroke Thecircuit" to'the solenoid 202 then is broken,'and the'spring' 244 restoresthe plunger 200 causing the 'dia'" phragm I98 to force the fuel'from the chamber 206. The contacts 254 do not again engage each" other until the plunger 200 is almost fully restored. The slip friction connection 252' includes a rubber ring 256 having a lost-motion c'onnec tion with the bolt 250 and frictionally clamped between a pair of spring fingers 258 secured tothe solenoid 202.- The spring fingers 258, by virtue of their frictional grip on the rubber body 256, retard the opening and closing of the'contacts 254 in the manner just described; This, insures a full stroke of the p1unger'200 in each direction for maximum working efliciencv ofthe i pumpvlu H a v The fuel pressure regulator I88, Fig. 15, has a.

fuel chamber 260'which in cons antlfcomn uni comprising the pilot 0 35? iris,

i. t t, I'll-- T e prin a e a 25. Qihe re ula r W8. s arr ngedtoi actuate contacts 264; Ijhe tension of the spring 266, a screw 26}. when the fuel pressure in the passage 2| 0 exceeds a e t m ned v l e; e e fiwt are sne prete mmga circuit from being closed to the solenoid 202f regardless of whether or not the contacts 254 are closed. The pump circuit re; mainsinterruptduntil the fuel pressure drops belowa given value; The chamber 260 serves to us ion the pressure pulsations of the pump 104. The bulk or each new i n. th t e m et ue l e edfirst to the'charnber 2.60, which functions as a reservoir." 'Thespring 2'66 yields to accommodate the charge, then gradually forces the fuel into the passage 2l'0: after? the power stroke of the pump hasended.

For. supplying] combustion air to the burners, there is mounted on the back'of the supporting plate 36 ajfan or blower 210 which ispoweredby a small electric motor" 212 located forwardly of; the plate36 A scroll2l4', Figs. 3 and 4 which is part o'fth'e" blower housing 216, surrounds the fan 210., and communicates with the inlet end of the air duct 60. 'A i r i's admitted to theinterior of the scroll 214: by means of a duct 218 extending diage au 'ro a short distance across the front of the mounting plat36. This duct 218 communicates 'at its opposite; ends respectively through openings in the plate 3 6 with the central portion of the space surroundinglthe fan 2'l0 and with the space. 280 within the blower housing 216-; exclusive of the scroll 214.: "Air issupplied to the;

space 280 by anfairf et pipe282 which ex? tends through the, wal l. d f th "bl1i 1diI 1g t-Q the outside. A hollowf. bushing 284 secured in the blower housing 216 as laterallv spaced coa gial, internally threaded portions 286 and 2 88 The air inlet pipe 282 threaded at itsim er end into the, portion 266 having the larger diameten Throughopenings' in the bushing 28 air, drawn from'the. pipe 282,in to the space 200,

thence through the'passage or. duct :2l8 into the I scroll 214,1byl'actionbf the fani 21o; The ir thenisimpelled bythefan 210 through the scroll 214,.

be t e nt k ic 91 s pl es i w. the plenum chambetlt in the vaporizer bloclc mie -ere "the auxiliary; 151 n cha 'Sunplementalor secondary air, which insures,

complete combustion: of the fuel supplied vaporizer blockl 10.1. These passages 2'90 ei itenid from the. plenum "chanr berv 18 w the recess l02. Fi s.' 3 an'd.10,in the front of the block 10.- Short tubes 292 are fittedinto r thefront ends'of the:

passages" 290 and project "from the block 10y throughthebaflle l06'g-{asshow'n in Fig. 9. Thesetubes292 di'scharg'e freshrair into the space with-- inthe burnerIrcaSe 4 0 .'for' wardly of the front plate 14,,thereby" insuring an; abundant supply of such'jadditional airIasfmay be'required for;

complete co' b tionof-the fuelwithin the com I bustion chambers or burner tubes 1 l2 and I Hi Refe'rringto 'Figs. 2 and'l'l, heat exchangertubes' 294 and" 29 6 in, the heat exchanger sections 38 respectively communicate with the opposite open ends ofthe burner tubes H2 and H4, That is 'to say, the combustion productsw from the burner tubel l2 aredischarged laterally at'b'oth ends thereof. intoj the heat. exchanger tubes 294 in the two sections 38,1and1ikewise, combustion productsfrom the tube H4 are dis-.

be: m

mesa se r ates-a 13 is such that substantially takes place within the burner tubes I I2 and I I4, so that only the hot combustion products (substantially without flames) pass into the heat exchanger tubes 294 and 296. The tubes 294 and 296 are provided with heat conducting fins 298. The heat exchanger tubes are made of suitable heat-resistant material such as cold-rolled steel coated with a ceramic compound, and the fins 298 are of copper or other highly heat-conductive material. Preferably the fins are bonded to the heat exchanger tubes in a single brazing operation by neutral-atmosphere heating and the tubes 294 and 296 are permanently bonded to the sides of the burner case 40.

The outlet ends of the heat exchanger tubes 294 and 206 38. The arrangement complete combustion case 40, to which they are bonded. The tubes and 304, like the tubes 294 and 296, are provided with heat-conductive fins 386.

The space within the burner case 40 surrounding the vaporizer block 10 to the rear of the front plate 94 communicates which is screwed into the smaller of the internally threaded portions 288 of the bushing 284. The body of fresh incoming air passing through the pipe 282 protects the wall of the building from the hot exhaust gases in the pipe 308. If these pipes are of any substantial length, a certain amount of preheating will be imparted to the incoming air by the exhaust pipe 308, thereby aiding the fuel vaporization process.

, Various automatic controls are included in the heater 22 for regulating its operation. The apswitches comprising a sweepout switch 3| 0, an igniter cut-out switch 3I2 and a pilot switch 3I4. In a relatively cool location on the heater, such as the back of the mounting plate 36, there is located an electrothermal switch 3I6. A ther mal temperature control device 3I8 and an overheat safety switch 320 are located in the inlet air stream of the heater. The functions of these various switches and control devices will be described more fully in connection with Fig. 20 hereinafter.

The temperature control device 3I8, as shown in Fig. 18, is mounted on a lever 322 which is pivoted to the mounting plates 36 and 324. The lever 322 depends from the pivot 324, and on the lower end of this lever there is mounted a bellows unit 326 filled with a thermally expansible a; given air. temperaturathere is provided a'con-a trol cam 330' mounted on the lower end of an operating shaft 332 that extends vertically in back of the mounting plate 36, on which it is jounialed. The shaft 332 is actuated by the control knob 34, Figs. 1, 3 and 17, to position the cam 330 selectively. A cam follower 334 on thelever 322 cooperates with the cam 330 for swinging the lever 322 inwardly or outwardly as the position of the cam 330 is changed.

An on-off switch 336, Figs. 18 and 19, is mounted on the front of the mounting plate 36. The forked actuating arm 338 of the switch 336 straddles a. pin 349 secured in the shaft 332, this pin extending through a clearance opening 342 in the plate 36. When the control knob 34 is turned to its oif position, the switch 336 is snapped 01f, thereby shutting down the heater. When the heater is to be started again, the control knob 34 is turned to a desired temperature-selecting position, automatically snapping the switch 336 on.

The operation of the heater will be described with reference to the circuit diagram, Fig. 20. To turn the heater on, the switch 336 is closed, establishing a circuit from the power supply line through a thermal limit switch 338 in the control device 3l8, thence through the cold contacts of the sweepout switch 3I0 to the motors 48 and 272, which respectively circulate the room air and supply combustion air to the burners.

Assuming that the overheat switch 320 is in its closed position, a circuit also is extended to the primary winding 340 of a step-down transformer 342. A secondary winding 344 on the transformer 342 is comiected to the input terminals of a rectifier bridge network comprising the sections 345, 346, 341 and 348 of the rectifier 349. The rectifier 349, upon being excited, supplies direct-current potential to the thermal switches 3I2, 3I4 and 3I6 and to the pressure regulator I88.

If the pressure regulator contacts 264 are closed, circuit is continued through the solenoid 202 of the fuel pump I84 and through the switch contacts 254 of the pump I84 to ground. The pump 984 thereupon starts operating, and. the solenoid 202 is alternately energized and deenergized by the closing and opening of the contacts 254 and 264 as described hereinabove. In order to prevent arcing of the contacts 254, a connection 356 is extended from the junction of the solenoid 202 and the contacts 254 back to a rectifier section 358 in the rectifier 349. The section 358 shunts the contacts 254 insofar as any inductive discharge from the solenoid winding 202 is concerned. The pump contacts 254 and the pressure regulator contacts 264 operate in timed relation with each other. The contacts 254 open first; then the contacts 264 open as the pump starts its forward The contacts 254 close at the end of this stroke, and thereafter the contacts 264 close as the fuel pressure subsides.

' The igniter cut-out switch 312 being cold, the igniter contacts 360 thereof are closed, whereas themain burner A circuit is extended from a secondary winding 3 current passing :through' theresistance winding 7 contacts 362 thereof are open.

The element 336 heats the thermal element-1,01 the switch 316, thereby causing the switch 316: to close its contacts so that a circuit. is established from the direct-current line through. switch 316 tothe igniter fuel valve solenoid. [9.0- However, if the igniter element 142 shouldbe'burned outer otherwise defective so that no current passes through it, the switch 316'. remainsopen, and; none of the fuel valves is permitted to open, under these circumstances.

Fuel being supplied to the igniter. 132,. an igniter flame is produced and. is projected through the vaporizer block 10. Passage of the igniter flame through the block Illheats the block, causing the pilot switch 31.4 to close- This, establishes a circuit from the direct-current line to the pilot fuel valve solenoid 133, which energizes and opens the valve to the pilot fuelline. Due to the initial heating of the vaporizer block, the pilot fuel is properly conditioned for com.- bustion, and a pilot flame is establishedwhen this fuel mixture contacts the igniter flame.

Heating of the vaporizer block is continued by the pilot flame, and when the block attains a predetermined temperature, the igniter' cut-out switch 312 changes from its cold position to its hot position. Contacts 360'thereupon open and interrupt the circuit to the igniter element 142 and also to the resistance winding 366 of the switch 316. and breaks the circuit to the igniter fuel valve solenoid 190, causing the igniter fuel valve to close. Thus, operation of theigniter is discontinued when the pilot flame hasv been established. The pilot switch 314. remains closed so long as the vaporizer block is heated.

The sweepout switch 310 (which is a snapaction thermal switch) changesfrom its cold" to its hot position as the heater temperature rises. This establishes a circuit through the hot contacts of the switch 310 to'the'motors 48 and 212 for maintaining these motors in operation independently of the switch 336. The purpose ofthis is to allow a scavenging operation to take place after theheateris switched off, whereby the motor 212 continues to draw fresh air through the combustion. chambers-of; the heater fora limitedinterval. This serves to cool the heateroff'rapidly and. to clear. thecom bustion, chambers vapor and combustion-products.

When the hot switch 312v close, acircuit lished to the temperature control switch is tentatively. estab- The switch 328 has contacts 3'10 and 312. which are respectively arranged to close at different. temperatures. If, for example, the air temperature is abnormally low so that a largequantity of heat is demanded, the position ofthe switch 328 is such that both of the contacts then is extended 3.10and 312 ar closed. Circuit from the direct-current line through'the contacts 362 of the switch 312 and thence through: 312 of the switch 328 to;

the contacts 310 and the main burner fuel valvesolenoids 191i and 192, Bothof the main burner fuel valves there fore are. opened, and conditioning passages 80 :and 841 inthe avaporizer: block 10'. Combustible mixture issupp-lied to. both the, mainburners mcderatei am nt: of heat Switch 316 thereupon opens and. heat. exchanger. of: fuel contacts 362. of the thermal fuel is delivered 1 to. the

under. these conditions... If the air; temperature issucn: that: only a... is. demanded; the switch 32 8 will assume a position suchthat .only e-co t t 0. rexamp1e;.,wil1 .beeclosedr 1m the: solenoid: 191:

The excess combustion air idle burner serves merely to dilute the exhaust gases at the'headers 300 without affecting combustion. at the other burners. If no heat or only a minimum quantity of heat is demanded, bothof th contacts 3'1lland 3'12 remain open, so that heat is supplied solely bythe pilot burner.

From the foregoing description it is apparent that'the temperature control device 318 operates to;-modulate the mainburners ofv the heater, by selectively opening and closing themain burner fuel valves in accordance with heat requirements; This is designed to maintain the air temperature within relatively close limits'at the selected value. If, for some reason, the air temperature should rise more than three degrees above the temperature setting, the limit switch 338 opens and interrupts the energizing circuit for the transformer 342, thereby preventing the delivery of fuel to the heater'until the temperature is reduced sufficiently to bring about closure of the switch 338.

If there should be a failure of. combustion suchas might lee-caused, forexample, by accidental extinguishment of the pilot flame; the heater cools and the thermal switch 31 2'changes from its -hot position to its cold" position; The contact 362 therefore opens and interrupts the circuit to the main burner valve solenoids I91 and 192. The contacts 360 close, thereby resulting in the energization of the igniter element 142 and the igniter fuel valve solenoid19o. The pilot switch 314 may' be designed to remain closed-until the heater has cooled to a considerably lower temperature, or it: may open concurrently with opening of the main burner contacts 362, as preferred. Assuming that thecondition which caused failure of combustion was not a permanent one, the igniter element 142 will reestablish combustion, causing the abovedescribed sequence of operations to be repeated. A conventional timing switch (not shown) may beincorporated in the control'system' to shut down the heater in the event ignitioncannot be established.

Iftheair circulating fan motor 48 shouldfail, or the air stream should be obstructed (as would occur if someone should place a towel or the like overthe opening 30, Fig. 1, of the heater) the-- temperature of the heater structure may become dangerously high. Under conditions such as these, the overheat switch 320' snaps openand interrupts the circuit to the transformer 342. The feeding of fuel to theheateris stopped and cannot be resumed until the'dangerous condition which produced overheating is removed. The overheat switch 320 must bemanually reset in order to place the heaterin operation again.

Summarizing the advantages of my-invention, I have provided aliquid fuel-consuming air heater which can be: more successfully employed in small and medium-sized installations than :eitherthe-.potitype. or theatomizing type of" hisz ituationc hessolsn ich 9221s insizeranmcheaper fonthe-samm-thezmalz output than either of the other types mentioned. The combustion chambers are small, and the power requirements are light.

The vaporizer block and associated parts of the burner assembly are very compact. In a commercial model of the invention, capable of delivering 40,000 B. t. u. or more per minute, the block it measures approximately four inches high, two and one-half inches wide and three inches long. Yet,'there is a sufficient depth of metal in the walls of the fuel conditioning passages to insure a high heat content and rapid transfer of heat to the fuel that is being conditioned. The flame, through the medium of the vaporizer block which acts as the heat storage body, furnishes all of the heat needed to condition the fuel for combustion. Cheap fuel such as kerosene or distillate may be successfully employed. The fuel is vaporized at a constant optimum temperature regardless of the number of main burners operating.

Low-cost parts are used throughout the heater. The burner tubes H2 and EM (which constitute combustion chambers for the main burners) and the heat exchanger sections 38 are made of lightweight, cheap material. The combustion air motor 272 is quite small, inasmuch as the combustion air pressure is not required to be very high (only a few inches of water above atmospheric pressure). The fuel feeding assembly Iii! is small and consumes very little power. The entire equipment is easy to install and is inconspicuous because of its small size and compactness.

The apparatus, moreover, is safe and dependable in its operation. None of the room air is used for combustion, and the exhaust fumes are discharged outside of the building. The heater is in full operation within 15 seconds after being turned on, irrespective of how cold the heater is when starting. Adequate controls prevent hazards due to combustion failure and overheating and serve to regulate the air temperature within close limits. The igniter 532 is, in effect, a small burner which performs its own fuel conditioning electrically. There is no need for high precision in the design of the igniter element 542, since the fuel is fed to the igniter at a very small rate and is preheated so that it has no appreciable cooling effect upon the igniter element. Other features and advantages of the invention not specifically mentioned herein will be apparent to those skilled in the art.

While there has been illustrated and described a preferred embodiment of the invention, this structure is capable of being modified in many ways without departing from the teachings set forth herein. The appended claims, therefore, are intended to cover all modifications coming within the true spirit and scope of the invention.

I claim:

1. A liquid fuel-consuming heater comprising a burner case, a vaporizer block disposed in said burner case, a main burner tube extending transversely across the front of said block, a nozzle extending from said block into said tube in tangential relation therewith, means on said block defining a pilot burner for igniting fuel issuing from said nozzle, fuel vaporizing passages extending through said block respectively to said nozzle and to said pilot burner means, devices for supplying liquid fuel and air to said vaporizing passages, a first heat exchanger tube communicating axially with said burner tube and extending lateraliy from said burner case, a second heat ex changer tube communicatin with said first heat I assembly 18 exchanger tube and extending back to said burner case, and an exhaust duct communicating with the space within said burner case adjacent to said block.

2. A liquid fuel-consuming heater comprising a vertical mounting plate adapted to be supported by a wall or the like, a burner assembly spaced from said wall, a supporting plate for said burner secured to said mounting plate, an air duct communicating with said burner assembly, said air duct extending through and being supported by said supporting plate and providing air for combustion to said burner assembly, a case enclosing said burner assembly, an exhaust duct connecting said case assembly to said supporting plate and providing a passage for removing exhaust gases from said case, heat exchanger tubes sealed to said burner case and extending laterally therefrom on either side thereof, said heat exchanger tubes providing a passage for products of combustion from said burner assembly to said burner case, and fins on said heat exchanger tubes.

3. In a heater of the internal having a fuel burning igniter, a plurality of main burners, Divine said main burners from a liquid fuel source, the combination of an electric igniter element adapted when energized to ignite fuel fed to said igniter for thereby establishing a flame to light the pilot burner, whereby a pilot flame is established to light the main burners, a plurality of electrically operable devices respectively controlling the flow of fuel to the main burners, a thermal switch having a normal cold position and responsive to heat from the pilot burner for assuming a hot position, said switch being connected to said igniter element and said devices and being effective in its cold position to cause e'nergization of said igniter element and preventthe operation of said devices and being effective in its hot position to cause deenergization of said igniter element and enabling said devices a pilot burner and to operate, means for controlling the flow of fuel to said igniter for providing fuel thereto only when said igniter element is energized, and means including a the *mal member responsive to the temperature of air heated by the heater and acting in conjunction with said thermal switch to close and open operating circuits for said devices selectively in accordance with heat requirements.

4. A liquid fuel-consuming air heater including in combination a heat-conducting vaporizing block having a first fuel-vaporizing passage extending therethrough terminating at the front of said block in a main burner port and having a second fuel-vaporizing passage extending therethrough terminating at the front of said block in a pilot burner port adjacent said main burner port; means for providing liquid fuel in each of said fuel conditioning passages; means for delivering air under pressure to each of said passages; an igniter mechanism for initially heating block to vaporize the fuel in said pilot burner vaporizing passage so that a combustible air-andfuel mixture is supplied to said pilot burner port,

and also for igniting said combustible mixture at said pilot burner port to develop a pilot flame;

and a baffle displaced from said block facing said pilot burner port for directing a portion of the pilot back against said vaporizing block to maintain said block within a selected temperarange to vaporize the fuel in said fuelvaporizing passages so that a combustible'ain" combustion type with means for sup-' fuel to said ignitor, said pilot burner and and-fuelmixture is supplied to said main burner port, and fordirecting another portion of the pilot flame to the main burner port for igniting the combustible mixture at the last mentioned port.

5. A liquid fuel-consuming air heater including in combination; a heat-conducting vaporizing block having a first fuel-vaporizing passage extending therethrough terminating at the front of said block ina main burner port, and having a second fuel-vaporizing passage extending therethrough terminating at the front of said block in a pilot burner port adjacent said main burner port; means for depositing liquid fuel in each of said fuel vaporizing passages; means for delivering air under pressure to each of said passages; an ignitor mechanism for initially heating said block to vaporize the fuel in said pilot burner vaporizing passage so that a combustible air-andfuel mixture is supplied to said pilot burner port, and also for igniting said combustible mixture at said pilot burner port to develop a pilot flame; a batlle displaced from said block facing said pilot burner port for directing a portion of the pilot flame back against said vaporizing block to maintain said block within a selected temperature range to vaporize the fuel in said fuel-vaporizing passages so that a combustible air-and-fuel mixture is supplied to said main burner port, and for directing another portion of the pilot flame to the main burner' port for igniting the combustible mixture at the last-mentioned port; a combustion chamber for said main burner port; and means of relatively low heat conductivity connecting said last-mentioned combustion chamber to said vaporizing block for supporting said chamber adjacent said main burner port whereby the temperature of said block is substantially unaffected by the combustion products from said main burner port.

6. A liquid fuel-consuming air heater including in combination; a heat-conducting vaporizing block having a first fuel-vaporizing passage extending therethrough terminating at the front of said block in a main burner port, having a second fuel-vaporizing passage extending therethrough terminating at the front of said block in a pilot burner port adjacent said main burner port, and havinga third passage extending therethrough terminating adjacent said pilot burner port; means for depositing liquid fuel in each of said fuel-vaporizing passages; means for delivering air under pressure to each of said fuel-vaporizing passages; an ignitor mechanism for establishing an igniter flame in said third passage initially to heat said blockhand vaporize the fuel in said fuel=vaporizingpassages so that a combustible airJ-and-fueI mixture is supplied to said pilot burner and main burner ports, and also to ignite said combustible mixture at said pilot burner port to develop a pilotflame; and means for directing a portion of said pilot. flame back against said vaporizing block to maintain said block in a heated condition and to direct'a portion of said pilot flame to said main burner port for igniting the 'combustiblermixture at the last-mentioned port.

'7. A liquid fuel-consuming air heater including in combinatioma heat-conducting vaporizing block having a first fuel-vaporizing passage extending therethrough terminating at the front of said block in a main burner port, having a second fuel-vaporizing passage extending therethroughterminatingiat the front of said block inJa' pilot burner: portadjacent said, main burner port, and having a third passage extending therethrough terminating adjacent said pilot burner port; means for depositing liquid fuel in said first and second fuel-vaporizing passages; means for delivering air under pressure to each of said fuel-vaporizing passages; and igniter mechanism for establishing an igniter flame in said third passage initially to heat said block and vaporize the fuel in said pilot burner vaporizing passage so that a combustible air-and-fuel mixture is supplied to said pilot burner port, and also to ignite said combustible mixture at said pilot burner port to develop a pilot flame; and a baffle supported adjacent said pilot burner port for directing a portion of the pilot flame against said vaporizing block to maintain said block within a selected temperature range to vaporize the fuel in said fuel-vaporizing passages so that a combustible air-and-fuel mixture is supplied to said main burner port, and for directing another portion of the pilot fiame to the main burner port for igniting the combustible mixture at the last-mentioned port.

8. A liquid fuel-consuming heater including in combination; a burner case; a vaporizing block disposed in said burner case having at least one fuel-vaporizing passage extending therethrough terminating at the front of said block in a mainburner port; a main-burner tube within said case extending transversely across the front of said block in communicating tangential relation with said main burner port; means for supplying liquid fuel to said fuel-vaporizing passage; means for supplying air under pressure to said vaporizing passage; means for heating said block to vaporize the fuel in said fuel-vaporizing passage so that a combustible fuel-and-air mixture is supplied to said main burner port, and for igniting said combustible mixture at said port; a U-shaped heat-exchanger means communicating axially with said burner tube and extending laterally from said burner case and back to the interior of said burner case; and an exhaust duct communicating with the space within said burner case adjacent the said block.

9. A liquid fuel-consuming heater including in combination a burner case; a vaporizer block disposed in said burner case having at least one fuel-vaporizing passage extending therethrough terminating at the front of said block in a main burner port; an open-ended main burner tube within said case extending transversely across the front of said block in communicating tangential relation with said main burner port; means for supplying liquid fuel to said vaporizing passage; means for supplying air under pressure to said vaporizing passage; means for heating said block to vaporize the fuel in said vaporizing passage so that a combustible fuel-and-air mixture is supplied to said main burner port, and for igniting said combustible mixture at said port; a first U-shaped heat-exchanger means communicating axially with one end of said burner tube and extending laterally from said burner case and back to the interior of said burner case; a second U-shaped heat-exchanger means communicating axially with the other end of said burner tube and extending laterally from said burner case and back to the interior of said burner case; and an exhaust duct communicating with the space within said burner case adjacent the said block.

- 10. A liquid fuel-consuming heater including in combination, a burner case; a vaporizing block disposed in said burner case having at least one fuel-vaporizing passage extending therethrough terminating in a main-burner port at the front of said block; a main-burner tube within said case extending transversely across the front of said block in communicating tangential relation with said main-burner port; means for supplying liquid fuel to said fuel-vaporizing passage; an air duct extending into said case and communicating with the rear of said block for supplying air under pressure to said vaporizer passage; a U-shaped heat-exchanger means communicating axially with said burner tube and extending laterally from said burner case and back to the interior of said burner case; and an exhaust duct communicating with the space within said burner case adjacent to said block.

11. A liquid fuel-consuming air heater including in combination, a heat-conducting vaporizing block having a first fuel-vaporizing passage extending therethrough terminating at the front of said block in a main-burner port for said air heater, having a second fuel-vaporizing passage extending therethrough terminating at the front of said block in a pilot-burner port adjacent said main burner port, and having a flame-directing passage extending therethrough terminating adjacent said pilot-burner port; an electrically-operated fuel-consuming igniter mechanism coupled to the back of said flame-directing passage:

means including an electrically-operated selector mechanism for supplying liquid fuel selectively to said first and second fuel-vaporizing passages and to said igniter; means for delivering air under pressure to each of said fuel-vaporizing passages and to said igniter; a first switching means initially closing a first energizing circuit to said selector when said block is in a relative cold condition to cause fuel to be supplied to said igniter, and initially closing an energizing circuit to said igniter whereby an igniting said flame-directing passage to heat said block; a thermally responsive switching means closing a second energizing circuit to said selector when flame is produced in I? 22 said block has reached a selected temperature to cause fuel to be supplied to said pilot-burner vaporizing passage, whereby a pilot flame is ignited at said pilot-burner port by said igniter fiame to further heat said block; a further thermally-responsive switching means closing a third energizing circuit to said selector when said block has reached a selected temperature higher than said first-mentioned selected temperature to cause fuel to be supplied to said mainburner vaporizing passage, whereby a mainburner flame is ignited at said main-burner port by said pilot flame; and a thermally-responsive element for opening said first switching means when said block has attained a temperature corresponding substantially to said second-mentioned selected temperature.

STANLEY J. BUDLANE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,349,876 Doble Aug. 17, 1920 1,394,807 Blanchard Oct. 25, 1921 1,656,486 Huntington et al. Jan. 17, 1828 1,688,435 Resek et a1 Oct. 23, 1928 1,832,220 Kerrihard et al. Nov. 17, 1931 1,841,463 Barber et a1. Jan. 19, 1932 2,073,073 Pontow et al Mar. 9, 1937 2,090,039 Goddard Aug. 17, 1937 2,332,094 McCollum Oct. 19, 1943 2,390,380 McCollum Dec. 4, 1945 2,390,806 Nagel Dec. 11, 1945 2,391,447 Edge Dec. 25, 1945 2,421,370 Budlane June 3, 1947 2,438,275 Fell et a1 Mar. 23, 1948 2,447,373 Smoot Aug. 17, 1948 2,457,862 Briskin Jan. 4, 1949 2,460,451 Farrell Feb. 1, 1949 2,465,711 Clarkson Mar. 29, 1949 2,484,385 McCollum Oct. 11, 1949 2,492,756 McCollum Dec. 27, 1949 

